A vane rotary compressor is used for an air conditioner and the like, and compresses a fluid such as refrigerant to supply the compressed fluid to the outside.
FIG. 1 is a cross-sectional view schematically illustrating a conventional vane rotary compressor disclosed in Japanese Patent Laid-open Publication No. 2010-31759 (Patent Document 1). FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1.
As illustrated in FIG. 1, the conventional vane rotary compressor, which is designated by reference numeral 10, includes a housing H, which is configured of a rear housing 11 and a front housing 12 while defining the external appearance thereof, and a cylindrical cylinder 13 which is received within the rear housing 11.
In this case, the cylinder 13 has an inner peripheral surface having an oval sectional shape as illustrated in FIG. 2.
In the inside of the rear housing 11, a front cover 14 is coupled to the front of the cylinder 13 and a rear cover 15 is coupled to the rear of the cylinder 13. A discharge space Da is defined between the outer peripheral surface of the cylinder 13, the inner peripheral surface of the rear housing 11 facing the same, the front cover 14, and the rear cover 15.
A rotary shaft 17 is rotatably installed to the front cover 14 and the rear cover 15 through the cylinder 13. The rotary shaft 17 is coupled with a cylindrical rotor 18, and the rotor 18 rotates in the cylinder 13 along with the rotary shaft 17 when the rotary shaft 17 rotates.
As illustrated in FIG. 2, a plurality of slots 18a are radially formed on the outer peripheral surface of the rotor 18, a linear type vane 20 is slidably received in each of the slots 18a, and lubricant oil is supplied into the slot 18a. 
When the rotor 18 is rotated by the rotation of the rotary shaft 17, a tip portion of the vane 20 protrudes outward from the slot 18a and comes into close contact with the inner peripheral surface of the cylinder 13. In this case, a plurality of compression chambers 21 are divided and formed, each of which is defined by the outer peripheral surface of the rotor 18, the inner peripheral surface of the cylinder 13, a pair of adjacent vanes 20, and a facing surface 14a of the front cover 14 and a facing surface 15a of the rear cover 15, which face the cylinder 13.
In the vane rotary compressor, an intake stoke is a stroke in which the volume of the compression chamber 21 is enlarged whereas a compression stroke is a stroke in which the volume of the compression chamber 21 is reduced, according to the rotation direction of the rotor 18.
As illustrated in FIG. 1, a suction port 24 is formed at the upper portion of the front housing 12, and a suction space Sa communicating with the suction port 24 is defined within the front housing 12.
The front cover 14 is formed with an inlet 14b which communicates with the suction space Sa, and a suction passage 13b, which communicates with the inlet 14b, is formed to axially pass through the cylinder 13.
As illustrated in FIG. 2, discharge chambers 13d, which are recessed inwards, are formed at the opposite sides of the outer peripheral surface of the cylinder 13. In this case, the pair of discharge chambers 13d communicate with the compression chambers 21 through associated discharge holes 13a, and forms a portion of the discharge space Da.
The rear housing 11 is formed with a high-pressure chamber 30 which is divided by the rear cover 15 and into which a compressed refrigerant is introduced. That is, the inside of the rear housing 11 is divided into the discharge space Da and the high-pressure chamber 30 by the rear cover 15. In this case, any one of the pair of discharge chambers 13d is formed with an outlet 15e which communicates with the high-pressure chamber 30.
Accordingly, when the rotor 18 and the vanes 20 rotate along with the rotation of the rotary shaft 17, a refrigerant is sucked from the suction space Sa via the inlet 14b and the suction passage 13b into each compression chamber 21. The refrigerant compressed by the reduction in volume of the compression chamber 21 is discharged to the discharge chamber 13d through the associated discharge hole 13a to be introduced into the high-pressure chamber 30 through the outlet 15e, and is then supplied to the outside through a discharge port 31.
Meanwhile, the high-pressure chamber 30 is provided with an oil separator 40 for separating the lubricant oil from the compressed refrigerant introduced into the high-pressure chamber 30. An oil separation pipe 43 is installed at the upper portion of a case 41, and an oil separation chamber 42, into which the separated oil is dropped, is formed in the lower portion of the oil separation pipe 43. The oil in the oil separation chamber 42 flows down into an oil storage chamber 32, which is formed in the lower portion of the high-pressure chamber 30, through an oil passage 41b. 
The oil stored in the oil storage chamber 32 lubricates a sliding surface between the rear cover 15 and rotor 18 via a lubrication space of a bush, which supports the rear end of the rotary shaft 17, through an oil supply passage 15d. Subsequently, the oil is reintroduced into the outlet 15e through an oil return groove 45 by a difference in pressure between the discharge space Da and the high-pressure chamber 30.
In the case of applying the linear type vane 20 to the conventional vane rotary compressor 10, since the vane 20 protrudes outward of the rotor 18 along the slot 18a, the tip portion of the vane 20 strikes the inner peripheral surface of the cylinder 13, thereby causing strike noise.
FIG. 3 is a cross-sectional view schematically illustrating a curved blade type vane rotary compressor disclosed in Japanese Patent Laid-open Publication No. 2002-130169 (Patent Document 2).
The vane rotary compressor illustrated in FIG. 3 includes a cylindrical cylinder 1, a rotor 2, and a drive shaft 3. In this case, the cylinder 1 includes an inlet 1A and an outlet 1B and the rotor 2 is eccentrically installed in the cylinder 1.
A plurality of curved blade type vanes 4 are provided on the outer peripheral surface of the rotor 2 so that a plurality of compression chambers 6 are divided and formed between the cylinder 1 and the rotor 2. One side of each of the vanes 4 is hinge-coupled to the outer peripheral surface of the rotor 2 by a hinge pin 5.
While the rotor 2 rotates by a predetermined angle from a time, at which a compression stroke ends when the vane 4 passes through the outlet 1B, to a time, at which an intake stroke begins when the vane 4 passes through the inlet 1A, the back portion of the vane 4 is pressed toward rotor 2 by the inner peripheral surface of the cylinder 1 as illustrated in the enlarged view of FIG. 3. In this case, the tip portion of the vane 4 is spaced apart from the inner peripheral surface of the cylinder 1.
Subsequently, when the force applied to the back portion of the vane 4 is instantaneously removed as a gap between the outer peripheral surface of the rotor 2 and the inner peripheral surface of the cylinder 1 is increased by rotation of the rotor 2, the tip portion of the vane 4 comes into contact with the inner peripheral surface of the cylinder 1 while the vane 4 pivots and is unfolded from the rotor 2.
In this case, when the vane 4 folded by the rotor 2 is unfolded toward the inner peripheral surface of the cylinder 1 due to an increase in rotational moment of inertia of the vane 4 during the high-speed rotation of the rotor 2, the tip portion of the vane 4 strikes the inner peripheral surface of the cylinder 1, thereby causing strike noise.
In addition, the back portion of the vane 4 comes into contact with the inner peripheral surface of the cylinder 1 at the initial stage of the intake stroke and the vane 4 is rapidly unfolded from the rotor 2 after the intake stroke somewhat proceeds, so that the tip portion of the vane 4 is supported by the inner peripheral surface of the cylinder 1. Therefore, the volume of the compression chamber 6 is not smoothly expanded, resulting in a reduction of suction flow rate.
This description will be given in more detail with reference to FIG. 4.
FIG. 4 is a partially enlarged view schematically illustrating forces acting on the curved blade type vane during the rotation of the rotor in FIG. 3.
In the vane rotary compressor illustrated in FIGS. 3 and 4, the vane 4 is unfolded from the outer peripheral surface of the rotor 2 during the rotation of the rotor 2. In this case, the tip portion of the vane 4 comes into close contact with the inner peripheral surface of the cylinder 1 so that the compression chamber 6 is defined between the pair of adjacent vanes 4.
The forces acting on the vane 4 will be described according to the action directions thereof with reference to FIG. 4. Centrifugal force A1 according to the rotation of the rotor 2 and rotational moment A2 according to a center of gravity M of the vane 4 act as forces of pushing and rotating the tip portion of the vane 4 toward the inner peripheral surface of the cylinder 1.
On the contrary, hinge friction force B1 of the vane 4, rotational moment of inertia B2, fluid resistance B3 in refrigerant of the compression chamber 6, friction force B4 between the vane 4 and the cylinder 1, and viscosity B5 of lubricant oil act as forces of pulling the tip portion of the vane 4 toward the outer peripheral surface of the rotor 2.
In this case, when the forces B1 to B5 of pulling the tip portion of the vane 4 toward the outer peripheral surface of the rotor 2 are larger than the forces A1 and A2 of pushing the tip portion of the vane 4 toward the inner peripheral surface of the cylinder 1, a gap is formed between the tip portion of the vane 4 and the inner peripheral surface of the cylinder 1.
In this case, the compression chamber 6 is not fully sealed by the vane 4 and an inner leakage occurs between the compression chamber 6 and the adjacent compression chamber 6, thereby causing a reduction of compression flow rate of the refrigerant.
In addition, the gap between the vane 4 and the cylinder 1 is gradually increased during a delay of rotation operation of the vane 4. Accordingly, there is a problem in that strike noise is caused when the tip portion of the vane 4 instantaneously comes into contact with the inner peripheral surface of the cylinder 1 due to the centrifugal force A1 according to the rotation of the rotor 2 and the rotational moment A2 of the vane 4.
In connection with the hinge friction force B1 of the vane 4, friction force is concentrated on a friction point Pf at which a hinge portion 4a of the vane 4 comes into contact with the outer peripheral surface of the rotor 2 when the vane 4 is unfolded. In this case, since an oil film 7 is formed only on one side of the friction point Pf, a reduction in friction force by lubricant oil may be decreased.
That is, when the hinge portion 4a of the vane 4 is hinge-coupled to a receiving groove 2a on the outer peripheral surface of the rotor 2, a portion of the hinge portion 4a is exposed outward from the outer peripheral surface of the rotor 2. Thus, the friction point Pf is formed on the sharp edge of the receiving groove 2a coming into contact with the hinge portion 4a during the rotation of the hinge portion 4a, and the oil film 7 by lubricant oil is formed only in the front region of the hinge portion 4a in the rotation direction thereof on the basis of the friction point Pf.
[Patent Document 1] JP2010-031759A (Feb. 12, 2010)
[Patent Document 2] JP2002-130169A (May 9, 2002)